1. Field of the Invention
The present invention relates to a color filter suitable for a color liquid crystal display which can be used in a color television, a personal computer or the like, a method for manufacturing the color filter, and a liquid crystal panel equipped with the color filter. More specifically, it relates to a color filter for liquid crystal displays manufactured by the utilization of an ink jet recording technique, a method for manufacturing the color filter, and a liquid crystal panel equipped with the color filter.
2. Related Background Art
In recent years, there has been a tendency that the demand of liquid crystal displays, particularly color liquid crystal displays increases with the development of personal computers, particularly portable personal computers. However, for the further spread of the liquid crystal displays, it is necessary to lower their costs, and particularly with regard to the color filter which largely occupies the cost of each display, request for its cost reduction increases. In order to meet the required characteristics of the color filter and to satisfy the above-mentioned demand, various attempts have been heretofore made, but any method which can meet all of the required characteristics has not been established so far. Some methods for manufacturing the color filter will be described below.
A first method which has most often been used is a dyeing method. This dyeing method comprises coating a glass substrate with an aqueous polymer material which is a material to be dyed, patterning the material into a desired shape by a photolithography process, and then immersing the thus obtained pattern in a dyeing bath to obtain a colored pattern. This operation is repeated three times to form the colored layers of Red (R), Green (G) and Blue (B).
Japanese Patent Application Laid-Open No. 5-288913 has described another example of this dyeing method which comprises forming a photosensitive layer, exposing it to light through a pattern, dyeing unexposed portions, and then repeating this process to manufacture a color filter having three colors of R, G and B.
A second method is a pigment dispersion method, which is now being replaced with the above-mentioned dyeing method. This pigment dispersion method comprises first forming, on a substrate, a photosensitive resin layer in which a pigment is dispersed, and then patterning the resin layer to obtain a single-colored pattern. Next, this process is repeated three times to form colored layers having three colors of R, G and B.
A third method is an electrodeposition method. This method comprises first patterning transparent electrodes on a substrate, and then immersing it in an electrodeposition coating solution containing a pigment, a resin, an electrolyte and the like to electrodeposit a first color. This process is repeated three times to form colored layers of R, G and B, and in the last step, these layers are calcined.
A fourth method is a printing method. This method comprises dispersing a pigment in a thermosetting resin, repeating a printing operation three times to coat with the colors of R, G and B, and then thermosetting the colored resin layers to form colored layers. In each of these methods, a protective layer is usually formed on the colored layers.
A point which is common to these methods is that a similar process is required to be repeated three times to give the three colors of R, G and B, which increases the cost. In addition, these methods having many steps lead to deterioration of a yield. Moreover, in the electrodeposition method, the formable patterns are limited, and so it is difficult to apply this method to TFT by an existent technique. The printing method has a drawback that resolution properties and smoothing properties are poor, and so it is not suitable for the formation of a pattern having a fine pitch.
In order to overcome these drawbacks, techniques for manufacturing a color filter by the use of an ink jet system have been developed, and these techniques have been described in Japanese Patent Application Laid-Open Nos. 59-75205, 63-235901 and 1-217320. However, a sufficiently satisfactory method has not been obtained yet.
Under such circumstances, an object of the present invention is to provide a method for manufacturing a color filter at a law cost in which necessary characteristics such as heat resistance, solvent resistance and resolution properties given by a conventional method are kept up, an ink jet suitability is satisfied, and a process for its manufacture is shortened; a highly reliable color filter manufactured by the above-mentioned method; and a liquid crystal panel equipped with the above-mentioned color filter. In particular, an object of the present invention is to provide a highly precise and reliable color filter for liquid crystals which can prevent color mixing and color skip when ink droplets are ejected by the use of an ink jet system to carry out the arrangement of colorants; and a method for manufacturing the color filter.
The aforesaid objects can be achieved by the present invention, as follows.
A first aspect of the present invention is directed to a color filter which comprises a substrate and a resin layer on the substrate, the resin layer containing a plurality of colored portions of different colors and non-colored portions.
A second aspect of the present invention is directed to a color filter which comprises a substrate having shade portions and light-transmittable portions and a resin layer on the substrate, the resin layer on the shade portions containing colored portions and non-colored portions.
A third aspect of the present invention is directed to a method for manufacturing a color filter which comprises arranging colorants on a substrate by an ink jet system, said method being characterized by comprising:
(1) a step of forming, on a substrate, a resin layer which can cure by light irradiation or the combination of the light irradiation and heating to reduce ink-acceptable properties of the layer,
(2) a step of curing portions of the resin layer by the light irradiation or the combination of the light irradiation and the heating,
(3) a step of providing with the colorants to uncured portions of the resin layer by an ink jet system, and
(4) a step of curing the colored portions of the resin layer by the light irradiation and/or the heating.
A fourth aspect of the present invention is directed to a liquid crystal panel which comprises a color filter described above, a substrate facing to the color filter, and a liquid crystal compound enclosed between both the substrates.
A fifth aspect of the present invention is directed to a liquid crystal panel which comprises a color filter described above, a substrate having shape portions arranged at a position opposite to the color filter, and a liquid crystal composition enclosed between the color filter and the substrate.
A sixth aspect of the present invention is directed to a method for manufacturing a color filter which comprises arranging colorants on a substrate by an ink jet system, said method being characterized by comprising:
(1) a step of forming, on a substrate, a resin composition layer which has an ink-acceptable property and in which the residue of a hydrophilic group in light irradiation portions decreases by light irradiation or the combination of the light irradiation and heating,
(2) a step of subjecting portions of the resin layer to the light irradiation or the combination of the light irradiation and the heating,
(3) a step of providing with the colorants to unirradiated portions of the resin composition layer by an ink jet system, and
(4) a step of curing the colored portions of the resin composition layer by the light irradiation and/or the heating.
A seventh aspect of the present invention is directed to a color filter which comprises a substrate having light-transmittable portions and a resin layer having the colored light-transmittable portions on the substrate, said resin layer being characterized by comprising at least (a) a homopolymer of a monomer comprising a structure unit represented by the following formula (I) and/or a copolymer of the above-mentioned monomer and another vinyl monomer, and (b) a compound selected from the group consisting of halogenated triazine compounds, diphenyliodonium salt derivatives and triphenylsulfonium salt derivatives: 
wherein R1 is hydrogen or a methyl group; and R2 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
An eighth aspect of the present invention is directed to a method for manufacturing a color filter which comprises arranging colorants on a substrate having shade portions by an ink jet system, said method comprising:
(1) a step of forming, on the substrate, a layer comprising a composition which has ink absorbency and in which the ink absorbency deteriorates in the portions of the composition treated by light irradiation or the combination of the light irradiation and a heat treatment,
(2) a step of subjecting the portions of the composition layer on the substrate to the light irradiation or the combination of the light irradiation and the heat treatment to deteriorate the ink absorbency of the irradiated portions,
(3) a step of ejecting ink droplets by the use of an ink jet system to color the untreated portions of the composition layer, and
(4) a step of subjecting the composition layer to the light irradiation and/or the heat treatment to cure the composition layer, said resin layer being characterized by comprising at least (a) a homopolymer of a monomer comprising a structure unit represented by the following formula (I) and/or a copolymer of the above-mentioned monomer and another vinyl monomer, and (b) a compound selected from the group consisting of halogenated triazine compounds, diphenyliodonium salt derivatives and triphenylsulfonium salt derivatives: 
xe2x80x83wherein R1 is hydrogen or a methyl group; and R2 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
A ninth aspect of the present invention is directed to a liquid crystal panel which comprises a color filter described in eighth aspect, a substrate arranged at a position opposite to the color filter, and a liquid crystal composition enclosed between the color filter and the substrate.
A tenth aspect of the present invention is directed to a method for manufacturing a color filter which comprises arranging colorants on a substrate having light-transmittable portions by an ink jet system, said method being characterized by comprising:
(1) a step of forming, on the substrate, a resin layer which can be rendered ink-acceptable by light irradiation or the combination of the light irradiation and heating,
(2) a step of rendering the resin layer on the substrate ink-acceptable by the light irradiation or the combination of the light irradiation and the heating,
(3) a step of providing with the colorants to the ink-acceptable portions of the resin layer by the ink jet system, and
(4) a step of curing the colored portions of the resin layer by the light irradiation or the combination of the light irradiation and the heating.
An eleventh aspect of the present invention is directed to a color filter manufactured by the method described in tenth aspect.
A twelfth aspect of the present invention is directed to a color filter which comprises a substrate and a resin layer having colored light-transmittable portions on the substrate, said resin layer being characterized by comprising at least (a) an acrylic resin having a structure unit represented by the following formula (V) and (b) a compound selected from the group consisting of halogenated triazine compounds, diphenyliodonium salt derivatives and triphenylsulfonium salt derivatives: 
wherein R1 is hydrogen or an alkyl group having 1 to 5 carbon atoms; R2 is an alkylene group having 1 to 5 carbon atoms or a phenylene group; R3 is an alkyl group having 1 to 5 carbon atoms, an alkyl-substituted silyl group, a phenyl group or a substituted aromatic group.
A thirteenth aspect of the present invention is directed to a method for manufacturing a color filter which comprises arranging colorants on a substrate by an ink jet system, said method comprising:
(1) a step of forming, on a substrate, a layer comprising a composition in which ink absorbency can be improved in the treated portions of the layer by light irradiation or the combination of the light irradiation and a heat treatment,
(2) a step of improving the ink absorbency of the portions of the composition layer by the light irradiation or the combination of the light irradiation and the heat treatment, and
(3) a step of ejecting ink droplets by the use of an ink jet system to color the treated portions of the composition layer, said resin layer being characterized by comprising at least (a) an acrylic resin having a structure unit represented by the following formula (V) and (b) a compound selected from the group consisting of halogenated triazine compounds, diphenyliodonium salt derivatives and triphenylsulfonium salt derivatives: 
xe2x80x83wherein R1 is hydrogen or an alkyl group having 1 to 5 carbon atoms; R2 is an alkylene group having 1 to 5 carbon atoms or a phenylene group; R3 is an alkyl group having 1 to 5 carbon atoms, an alkyl-substituted silyl group, a phenyl group or a substituted aromatic group.
A fourteenth aspect of the present invention is directed to a color filter manufactured by a manufacturing method described in thirteenth aspect.
A fifteenth aspect of the present invention is directed to a liquid crystal panel which comprises a color filter described in twelfth aspect, a substrate arranged at a position facing to the color filter, and a liquid crystal composition sealed between the color filter and the substrate.